1. Field of the Invention
The present invention relates to an image forming apparatus having an opening and closing member that is able to opened with respect to an apparatus main body to open the inside of the apparatus main body.
2. Description of the Related Art
In a conventional image forming apparatus adopting an electrophotographic method, such as a copying machine, a printer, or the like, an opening and closing door (opening and closing member) is provided, which rotates with respect to the apparatus main body to be openable and closable, and opens the inside of the apparatus main body to enable maintenance such as replacement of a cartridge, or the like or jam handling.
FIG. 15 is a perspective view of a conventional image forming apparatus 901, which has the opening and closing door 904. FIG. 16A is a cross-sectional view illustrating parts of the opening and closing door 904 and the apparatus main body 901 around the opening and closing door 904, and illustrates a closed state of the opening and closing door 904. The opening and closing door 904 is opened to rotate in the direction of an arrow in FIG. 10 with a rotation shaft 904r as an axis. Herein, in general, the opening and closing door 904 is configured to press a member 907 in the apparatus main body 901 while closing the opening and closing door 904, to open and close a laser shutter (not illustrated) in the apparatus main body 901 or to turn on and off electrification to an interlock (not illustrated) in conjunction with opening and closing of the opening and closing door 904. As a result, the opening and closing door 904 is configured to receive reaction force Fs from the member 907 in the apparatus main body 901 while closing the opening and closing door 904. Therefore, engaged portions 905a and 905b, which engage with engaging portions 906a and 906b of the apparatus main body 901, are provided at both ends in the direction of the rotation shaft 904r of the opening and closing door 904 as illustrated in FIG. 16A, to keep the opening and closing door 904 being closed with respect to the apparatus main body 901.
In this configuration, for example, if a user closes the opening and closing door 904 by moving the opening and closing door 904 with force Fu along a right side of the opening and closing door 904 in FIG. 16B, the following phenomenon may occur. That is, as illustrated in FIG. 16B, at the right side of the opening and closing door 904 in FIG. 16, the engaging portion 906b engages with the engaged portion 905b, but the engaged portion 905a cannot engage with the engaging portion 906a due to the reaction force Fs at the left side of the opening and closing door 904 in FIG. 16B. In this state, the opening and closing door 904 is bent at an angle θ as compared with an initial state. This state is a state called a ‘one-sided closing state’ and in this state, the apparatus may not normally operate.
In particular, since the member 907, which applies the reaction force Fs to the opening and closing door 904, is mostly located at an end portion of the opening and closing door 904, the one-sided closing state easily occurs when the user operates the opening and closing door 904 by pushing a portion of the opening and closing door 904 where the member 907 is not located.
Therefore, Japanese Patent Application Laid-Open No. 2006-53193 discusses a configuration to detect the one-sided closing state by the use of a detection unit when the one-sided closing state occurs, and to prevent an image forming operation from starting when the one-sided closing state is detected.
However, in the configuration discussed in Japanese Patent Application Laid-Open No. 2006-53193, since the detection unit, which detects the one-sided closing state, needs to be provided, cost increase may be caused and the apparatus may be larger. Further, preventing the one-sided closing state by increasing rigidity of the opening and closing door is also considered, but there is a limit in increasing the rigidity of the opening and closing door in terms of cost or miniaturization.
Therefore, Japanese Patent Application Laid-Open No. 2009-271408 discusses a configuration in which the opening and closing door itself cannot be closed if the opening and closing door is not closed at a predetermined position to prevent the one-sided closing state.
However, in the configuration discussed in Japanese Patent Application Laid-Open No. 2009-271408, since the opening and closing door itself cannot be closed if the opening and closing door is not closed at the predetermined position, the user needs to perform an operation of closing the opening and closing door many times to close the opening and closing door, and there is a room for improvement of usability.